The present disclosure relates to a radiation irradiation apparatus that irradiates, with radiation, a subject to be examined in the case that a radiographic image of the subject to be examined is obtained.
Conventionally, various radiography apparatuses using movable radiation irradiation apparatuses were known, for example, as disclosed in Japanese Unexamined Patent Publication No. 2009-131323 (Patent Document 1), Japanese Unexamined Patent Publication No. 2007-029353 (Patent Document 2) and Japanese Unexamined Patent Publication No. 2010-119485 (Patent Document 3). Such a radiography apparatus is basically configured to irradiate, with radiation, a subject to be examined by using a doctor's-round-visit-cart-type radiation irradiation apparatus including a leg unit made travelable by wheels, a main body part that houses a battery for driving a radiation source and an electrical circuit related to drive of the radiation source and is held on the leg unit, an arm unit connected to the main body part, and the radiation source attached to the arm unit.
Further, a radiography apparatus using a portable-type radiation irradiation apparatus on which only minimum composition elements, such as a radiation source and an electrical circuit, are mounted, and which is held by hand and operated by an operator, has also been proposed (please refer to Japanese Unexamined Patent Publication No. 2012-029889 (Patent Document 4)). The weight of such a portable-type radiation irradiation apparatus has been reduced to such an extent that an operator can operate the apparatus by holding the apparatus by hand. Therefore, more flexible radiography has become possible than the aforementioned doctor's-round-visit-cart-type radiation irradiation apparatus.
In the case that a radiographic image of a subject to be examined is obtained by radiography by such a radiography apparatus, normally, a radiation detector (so-called “Flat Panel Detector”), which is irradiated with radiation that has passed through the subject to be examined and thereby records a radiographic image representing the subject to be examined, is used. As such a radiation detector, a cassette-type radiation detector, in which an image detector, a battery for driving, and a control unit of an electrical circuit related to drive or the like are housed in a housing, is known. Further, in the case that such a radiation detector is placed at a position facing a radiation irradiation apparatus with a subject to be examined therebetween, and the radiation irradiation apparatus is driven in the state, radiation that has passed through the subject to be examined irradiates the radiation detector, and a radiographic image represented by the radiation that has passed through the subject to be examined is obtained.
Further, in a radiography apparatus in which a radiation irradiation apparatus and a radiation detector are separate from each other, as described above, a technique for obtaining a photographic image representing a surface of a subject to be examined by performing photography on the subject to be examined by a camera and displaying the photographic image has been proposed to recognize an irradiation field and the like (please refer to Patent Documents 1 through 3). Further, in a radiography apparatus in which a radiation irradiation apparatus and a radiation detector are separate from each other, a difference in position tends to occur between an irradiation field of radiation and a detection range of the radiation detector. Therefore, in Patent Documents 1 through 3, a technique for performing superimposed display of a frame representing an irradiation field of radiation and a frame representing a detection area of a radiation detector on a displayed photographic image has been proposed.